The generating function is algebraic: closed forms and the growth constant 32/3 for the extension closed subcategories of a uniformly oriented Aₙ₊₁ quiver
Abstract
Let Rₙ be the number of full, additive, idempotent split subcategories of Aₙ₊₁-mod closed under extensions, for a uniformly oriented quiver of type Aₙ₊₁ — the OEIS sequence A393920 — and let Pₙ be the number of those containing a distinguished point of the associated triangular array; Pₙ counts the convex topologies on an (n+1)-element chain, OEIS A234268. Mazorchuk proved 9ⁿ<Rₙ<12.75ⁿ for ngg0 and wrote of the true growth rate, which his data put "probably somewhere around 10.5", that finding non-trivial bounds "is not really easy". We show that both generating functions are algebraic. Summing his own interlaced recurrences over their second index produces a polynomial equation with one catalytic variable, and the quadratic method collapses it to the cubic 27u³-36u²+8u+1+16xu²+xP=0, u=1-x-x²P, and to the rational parametrisation x=(Y-1)/(Y²(3Y-2)), P=Y²(3Y-2)(1+Y-Y²), R=Y²(3Y-2)(5-3Y). Lagrange inversion then gives single binomial sums for both sequences and two-term recurrences with polynomial coefficients — formulas that neither OEIS entry carries. The singularity is located exactly: x=3/32, a triple root of the discriminant. Three classical steps of singularity analysis, which we isolate and do not verify formally, then give lim Rₙ^(1/n)=lim Pₙ^(1/n)=32/3, with Rₙ ∼ frac(768, 25√(5π))n^(-5/2)(32/3)ⁿ and Rₙ/Pₙ → 81/64. In the effective direction we carry Mazorchuk's truncation scheme to bases 10.3 and 10.4 with minimal levels and least integer constants, verify the base-10 bound his paper records as unverified, give the first explicit growth bounds for A234268, and explain the scheme's ceiling: its rungs converge to 32/3 and never reach it. The algebraic identities and every arithmetic claim are verified in Lean 4.
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Source snapshot 2026-08-30 15:34 UTC
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Claim ledger
Stated results
Q1candidate2026-08-28
The 10ⁿ lower bound Microsoft Copilot asserted and the source could not verify: Rₙ >= 10ⁿ / 111 for every n, at truncation level L = 159
Q2candidate2026-08-28
L = 159 is the minimal truncation level at which base 10 is reachable (the source's remark quotes L = 160)
Q3candidate2026-08-28
111 is the least constant for base 10: 110 * R₃6 < 10³6
Q4candidate2026-08-28
Rₙ >= (10.1)ⁿ / 165 for every n, at the minimal truncation level L = 195, with 165 least (164 fails at n = 42)
Q5candidate2026-08-28
Rₙ >= (10.2)ⁿ / 267 for every n, at the minimal truncation level L = 247, with 267 least (266 fails at n = 53)
Q6candidate2026-08-28
Where the method stops: F_L(11) > 0 at every truncation level L <= 247, and 111 * R₁2 < 11¹2
Q7known2026-08-28
The source's own Theorem: Rₙ >= 9ⁿ / 12 at its truncation level L = 47, reproduced; and its constant 12 is least (11 * R₁1 < 9¹1)
Q8routine2026-08-28
Non-vacuity: n -> 2 * 11ⁿ satisfies every hypothesis of the main theorem, and the tabulated Rₙ satisfy the source's truncated inequality for 161 <= n <= 248
Q9known data2026-08-28
Provenance of the tables: the source's a/b recurrence run inside Lean to n = 248 generates both W₀..W₂48 and R₀..R₂48; all 21 OEIS A393920 terms, all 48 Wₜ printed in the source and all 10 OEIS A234268 terms are reproduced exactly
Q10known data2026-08-28
The tables agree with the source's DEFINITION, not only its recurrence: brute force over Condition (star) reproduces R₀..R₅ = 2,7,34,199,1308,9300 and P₀..P₅ = 1,4,21,129,876,6376
Q11routine2026-08-28
The maximal root of the source's own F₄7, of which the PROOF of its Corollary 21 says (not the statement – corrected 2026-08-28) 'we do not know exactly what it is': 9.0116 <= rho₄7 < 9.0117; hence Rₙ >= (9.0116)ⁿ / 12 at the source's own truncation level L = 47 and with its own constant 12, which is least there too (11 fails at n = 10)
Q12candidate2026-08-30
The lossless ladder: the source's own proof contains the exact recurrence Rₙ = 2Rₙ₋₁ + sum_(t<n) (Wₜ+Pₜ) Rₙ₋ₜ₋₂ (kernel-checked on the whole table), and its truncations strictly lower every minimal level of the family's ladder — base 9 at L = 45 (source: 47), base 10 at L = 155 (was 159), 10.1 at L = 191 (was 195), 10.2 at L = 242 (was 247) — with the same least constants 12, 111, 165, 267
Q13candidate2026-08-30
The ceiling does not move: bases 10.3 and 11 are unreachable at every level L ≤ 248 even on the lossless ladder (G_L ≤ F_L, so each failure implies the W-ladder one) — the convolution the source discards was not the obstruction; externally the same holds to L = 319 and the max reachable base moves only 10.2017 → 10.2098 at L = 248
Q14candidate2026-08-30
The first explicit growth bound for OEIS A234268 (convex topologies on an (n+1)-point chain; Tamari interval preposets): Pₙ ≥ 9ⁿ/16, Pₙ ≥ 10ⁿ/144, Pₙ ≥ (10.2)ⁿ/344, each constant least (15/143/343 fail at n = 10/36/53), via the source's Lemma P-exact truncated — not via its §7.2 sandwich, which would give 24/222/534
Q15routine2026-08-30
Controls for the lossless and P packages: explicit witnesses satisfying every hypothesis (Rs = Ps = 2·11ⁿ), and the real tables satisfy the truncated hypotheses at the checkable levels
Q16known data2026-08-30
The P table: P₀…P₂48 (A234268 offset by one) held as literals and pinned to Wfull/Rdata in the kernel by the source's Lemma P-exact; the 21 values of the source's Figure 1 (of which the first 10 are the entire OEIS entry) reproduced exactly
Q17candidate2026-08-30
The generating functions of A393920 and A234268 are ALGEBRAIC: summing the source's own a/b recurrences over the second index gives a quadratic equation for B(x,y) with catalytic variable y, and the quadratic method collapses it to 27u³-36u²+8u+1+16xu²+xP = 0 with u = 1-x-x² P, equivalently the rational parametrisation x = (Y-1)/(Y²(3Y-2)), P = Y²(3Y-2)(1+Y-Y²), R = Y²(3Y-2)(5-3Y); the parametrisation satisfies the cubic identically (ring) and the tabulated P satisfies it on x⁰..x¹60 in the kernel
Q18candidate2026-08-30
The algebraic certificates that locate the singularity: the numerator of dx/dY is -Y(3Y-4)(2Y-1); its roots 1/2 and 4/3 are the branch points, Y = 0 being a POLE; x(4/3) = 3/32 and x(1/2) = 4 exactly; the RESULTANT res_P(E, dE/dP) of the un-normalised form (leading coefficient -27x⁶) is 27x¹5 (32x-3)³ (x-4) – equivalently the discriminant of the NORMALISED cubic is x⁵ (32x-3)³ (x-4) – a TRIPLE root at 3/32; and 32/3 is a root of the reciprocal quartic 108L⁴-3483L³+37728L²-140288L+32768
Q19prose2026-08-30
The exact growth rate, which the source says it does not know ("the limit probably somewhere around 10.5"): lim Rₙ^(1/n) = lim Pₙ^(1/n) = 32/3 = 10.666..., with Rₙ (768/(25 sqrt(5 pi))) n^(-5/2) (32/3)ⁿ, Pₙ (49152/(2025 sqrt(5 pi))) n^(-5/2) (32/3)ⁿ and Rₙ/Pₙ -> 81/64; this replaces the source's 9ⁿ < Rₙ < 12.75ⁿ by a single constant
This ledger entry is reported in prose and is not bound to a Lean theorem.Q20candidate2026-08-30
A formula for two OEIS entries that carry none: Rₙ = (1/n)tⁿ⁻¹(1+t)²ⁿ⁺¹(1+3t)ⁿ and Pₙ = (1/n)tⁿ⁻¹(1+t)²ⁿ⁺¹(1+3t)ⁿ, and the two-term recurrences 16(n+1)(2n+3)(5n+14)Rₙ + 6(n+4)(2n+7)(5n+9)Rₙ₊₂ = (655n³+4469n²+10090n+7536)Rₙ₊₁ and 16(n+1)(2n+7)Pₙ + 6(n+4)(2n+9)Pₙ₊₂ = (131n²+789n+1162)Pₙ₊₁ — derived from the parametrisation by an exact rational-function ODE certificate, kernel-checked on 519 terms
Q21routine2026-08-30
Controls for the deep package: the 519-term tables extend the landed Rdata/Pdata/Wfull/Vfull exactly, satisfy the source's Lemma P-exact and the lossless exact recurrence on their whole length, satisfy the truncated hypotheses at the levels the new rungs use, are dominated by 2*11ⁿ, and both hypothesis packages have explicit witnesses
Q22candidate2026-08-30
Two new rungs of the source's ladder: Rₙ >= (10.3)ⁿ/485 at minimal level L = 325 (lossless) / 331 (the source's own ladder) and Rₙ >= (10.4)ⁿ/1071 at L = 475 / 483, both constants least (484 fails at n = 68, 1070 at n = 96), with the matching bounds Pₙ >= (10.3)ⁿ/623 and Pₙ >= (10.4)ⁿ/1369, also least; and the ceiling, now explained: 10.45, 32/3, 10.7 and 11 are subsolutions at no level L <= 518 (those four theorems are tagged Q21, not this row), and – CONDITIONALLY ON THE GROWTH THEOREM, not by kernel check – no base >= 32/3 ever is
Provenance
- Generated by
- Machina Mathematica
- Released by
- Korea Superintelligence Labs
- Source context
- Source. Volodymyr Mazorchuk, *On the number of extension closed additive subcategories for uniformly oriented Aₙ quivers*, arXiv:2607.00651v1 (math.RT, submitted 2026-07-01; still v1 as of 2026-08-28).
- Snapshot
- 2026-09-07 03:53 UTC
- Ledger commit
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